Process of making slips for casting earthenware articles.



CHARLES J. KIRK, OF NEW CASTLE, PENNSYLVANIA.

PROCESS 01E MAKING SLIPS FOR CASTING EABIHENWARE ARTICLES.

L23Al1lt No Drawing.

To all whom it may concern:

Be it known that I, CHARLEs J. Kink, a citizen oi the United States,residing at New Castle, in the county of Lawrence and State ofPennsylvania, have invented new and useful Improvements in Processes ofMaking Slips for Casting Earthenware Articles, of which the following isa specification.

This invention relates to improvements in ceramics and more particularlyto an improved process of making a slip for casting earthenwarearticles.

The art of forming earthenware articles by casting from liquid slip hasbeen recognized in the ceramic industry for some time but has not comeinto commercial prominence until recent years. Heretofore mostcommercial earthenware articles were formed by pressing and the clay wastreated in the following manner for this process: The ball clays, chinaclays, flint and spar weighed in a scale in the exact proportions andplaced in a blunger with the proper amount of water and blunged untilthoroughly mixed and liquefied, the. slip so formed was run. through alawn or screen and pumped into a filter press under about sixty poundspressure taking out the water and leaving the clav about the consistencyof putty which was then ready for pressing. When casting from slip cameinto vogue it was discovered that a slip made from the putty-likepressing clay would not cast properly but would do so upon adding to theslip-so formed certain proportions of soda salts. As far as known, allcasting slips have heretofore been made by mixing and treating theingredients as above described in the formation of pressing clays andfilling a second blunger about onequarter full of the slip from thefirst blunger, before it had been passed through the filter press. Saltsin the form of silicate of soda and carbonate of soda, together withcakes of pressing clays were then added and blunged until the slipformed in the second blunger weighed about twenty-eight ouncesto theAmerican pint. This slip after having been run through a second lawnyorscreen and over magnets, to take out the iron, was then ready forcasting. The proportions and ingredients forming this casting. slipSpecification of Letters Patent.

Patented Unit. 31, 19316.

Application filed December 29, 1913. Serial No. 809,406;

have been determined, by experience and therefore, as far as known, allpotteries engaged in the casting art have, since the time that artoriginated, continuously employed the above described process for makingcasting slips, believing it necessary to first form the pressing clayand then add the salts to the pressing clay in asecond blung'er in orderto form a casting slip of the desired character.

This invention contemplates the making of the casting slip in a singleblunger and thereby doing away with the filter press and handling of thepressing clay which reduces the time and cost of making materially.

In accordance with this invention it has been discovered that instead offirst placing the ball clays, china clays, the flint, spar and water inthe blung r, if the ball clays, water and salts are first thoroughlyblunged and then the other ingredients added a casting slip of a propercharacter is formed. This improved process employs a single blunger inwhich are placed ball clays, water and salts and thoroughly blunged towhich is then added the china clays, flint, spar and scraps from thecasting shop and blunged until the proper weight is secured. This slipafter having been run through a lawn or screen and over magnets is thenready to be conveyed to the molds. The proportions of the ingredients inthis slip are not a part of this invention, as the proper proportionsfor forming a casting slip are well known in the art and everymanufacturer uses a different formula.

This improved process is adapted for use in producing a slip for castingany kind of earthenware articles.

What I claim is:

The process of making slip for easting earthenware articles comprisingthe thorough blunging of ball clays. water and soda salts in the properproportions in a blunger and then adding china clays, flint and spar inthe proper proportions until the desired weight is obtained.

CHARLES J. KIRK.

Witnesses NORMAN A. MARTIN, N. CUNNINGHAM.

topics of this patent may be obtained for five cents each. by addressingthe Commissioner of .Patents, Washington, D G.

